1. Field of the Invention
The present invention relates generally to communications networks and more specifically to a multi-network communication system in which the user can select one of a plurality of communications networks owned and operated by different service providers.
2. Description of the Related Art
There are a number of communications networks owned and operated by different service providers. Users compare the service features of the networks to select one that meets their desired feature and purchase a mobile terminal of the selected network. In a service area where networks of different service providers co-exist one network may be carrying heavy traffic while another is carrying light traffic with a sufficient remaining capacity to handle new calls. In such instances, it is desirable for users to access the light-traffic network. To meet this objective, a multi-network user terminal has been developed to allow the user to use a desired one of the networks the terminal can access. However, none of these networks sends back a response signal that indicates the current level of network traffic. Therefore, the user has to arbitrarily choose one network and makes a call attempt. If congestion is encountered, the user abandons the call and switches over to another network and repeats the same process. The process may be repeated until the user encounters a network that can complete the call.
Therefore, a need does exist to provide a multi-network environment that allows users to receive services from a number of communications networks without the need for making a manual switchover from one network to another.